According to the present invention, an absorbent article is described having improved absorbency characteristics and a method of making the same. More particularly, the present invention describes an absorbent core of an airlaid material having an embossed pattern on its top surface. The use of absorbent articles has become quite prevalent in today's world.
They have been improved and modified so as to have varying shapes, sizes, and characteristics as per the particular application. For example, baby diapers are large smooth articles with high absorbent capacity, thus making it possible for the baby to wear the article for a long period of time. At the same time, sanitary pads or pantiliners worn by females are relatively small articles that are not noticeable from the outside, thus avoiding the wearer any embarrassment.
One of the areas in this field where a significant amount of research has been done is in the construction of the absorbent core of the article. The absorbent core, generally, absorbs and retains body fluids so that they can be easily disposed of.
In order to improve the absorbency, retention and other desired properties of the core, various natural and synthetic materials have been introduced in its construction. The objective being that the core should be an optimized result of the weight of its constituents and the absorbency and retention it offers.
In the most simplistic construction of an absorbent article, this core is disposed between a liquid permeable body facing top sheet and a liquid impermeable garment facing back sheet. However since this portion forms the bulk of the article, it contributes significantly to the comfort factor when the article is worn. More so, when the article is worn, this portion is disposed in the crotch region of the wearer, where even a slight amount of discomfort is least desirable.
Furthermore, since a combination of natural and man made fibers and other materials are used in making an efficient absorbent core, it is important to bind the materials together so as to provide uniformity as well as strength. In order to provide the desired amount of strength, softness, as well as looks, one common approach in the field is to bind the absorbent core fibers by embossing the core.
The embossing also achieves a combination of high density embossed regions and/or lines along with low-density non-embossed regions. This combination creates lines, or depressions, in the absorbent core that aid in an efficient absorption of the body-released fluids.
U.S. Pat. No. 4,518,451, issued to Luceri et al., discloses an embossed pantiliner where the body facing side is imposed with a relatively deep pattern of depressed areas, and the longitudinal edges are imposed with a pattern of relatively shallow depressed areas. This results in a pantiliner that has aesthetically effective embossing while providing comfortable longitudinal edges.
U.S. Pat. No. 4,623,340, issued to Luceri, discloses an absorbent pantiliner provided with a pattern of depressed areas. The outer cover of the pantiliner is made from a relatively light opaque sheet material and the interior layer is at least partially thermoplastic and relatively dark colored. When the cover is embossed, the depressed areas appear darker than the un-embossed areas.
U.S. Pat. No. 5,514,104 issued to Cole et al., discloses an absorbent article comprising an absorbent core having a body-facing side and a garment-facing side. The garment facing side of the absorbent core, i.e. bottom layer, is embossed to form a pattern of areas of differing density. The embossed pattern on the bottom layer of the absorbent core improves the removal of urine or other fluids from the discharge zone to be ready for the next void.
U.S. Patent Publication No. 2004/0267220 of Raymond, describes an absorbent article having an embossing pattern defined as a raised portion on an upper layer. The embossing pattern of a type letter, word, mark, hatch line, number, logo, etc, is applied. However, the embossing pattern with diamond or square edges is observed to be stiff to the wearer.
The disclosure of the aforementioned patents and publications are incorporated herein by reference thereto in their entirety.
Owing to the nature of the embossing procedure and the embossed design pattern, the absorbent core is not very smooth or comfortable when worn close to the body. If the pattern is polygonal, it makes the whole core very rigid. Sometimes the edges of the polygon also add to the discomfort of the wearer.
Furthermore because of the polygonal nature of the pattern, narrow channels are formed thereby limiting the storage capacity for the liquid that is yet to be absorbed by the core.
It is therefore desirable to have a configuration of the absorbent core that is comfortable to be worn as well as offering enhanced absorption properties.
It is an objective of the present invention to provide an improved core that is smooth to the body and comfortable to wear.
It is a further objective of the invention to provide a core with increased fluid storage and retention capacity.
It is yet another objective of the present invention to have desired rigidity in the absorbent core.